eIDAS explained: AdES, QES and QSeal for documents
9 July 2026 · 8 min read · Nextarp B.V.
Under the EU eIDAS regulation, not all electronic signatures carry the same legal weight. Choosing the right level is the difference between a signature a court accepts without question and one you have to defend. This guide breaks down the tiers in plain language.
The three signature levels
- Simple electronic signature (SES) - any electronic mark of intent, from a typed name to a checkbox. Legally admissible but easy to dispute.
- Advanced electronic signature (AdES) - uniquely linked to the signer, capable of identifying them, created with data under their sole control, and tamper-evident. This is where cryptography enters: a certificate binds identity to the document.
- Qualified electronic signature (QES) - an AdES created with a qualified signature-creation device and backed by a qualified certificate from a trust service provider on an EU trusted list. A QES has the legal equivalent of a handwritten signature across the EU.
Electronic seals (QSeal)
Signatures belong to people; seals belong to organisations. A qualified electronic seal (QSeal) proves a document originated from a legal entity and has not been altered - ideal for invoices, certificates and bulk correspondence where no single person signs.
How to choose
Match the level to the risk and the regulation. Internal approvals rarely need more than AdES. Contracts, notarial acts and cross-border filings often demand QES. High-volume issuance from an organisation is the classic QSeal use case.
Where DocsNG fits
DocsNG produces PAdES signatures at AdES, QES and QSeal levels, using local certificates or keys held in a cloud KMS or HSM, with qualified timestamping. You select the assurance level per template or per request, so the same platform covers a low-risk internal memo and a qualified-signed cross-border contract.
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